This invention relates to improvements in the method and means for igniting a fuel mixture used in internal combustion engines.
At the present time there is great interest in extending the useful operating range of an internal combustion engine to much leaner combustible mixtures, where there is a potential for an increase in engine efficiency (reduced fuel consumption) and which decreases the combustion temperature thereby reducing the production and subsequent emission of Nitrous Oxides.
The conventional ignition system consists of a high voltage (low energy of approximately 0.1 joule) "spark" discharge in the combustible mixture. The "spark" ignites a small volume of the mixture which in turn spreads through the combustion chamber at the speed of the flame front.
Conventional internal combustion engine efficiency is presently limited by the flame speed, which becomes slower as the fuel/air mixture ratio is lowered. Secondly, variations in the ignition delay time between cylinders and/or firings in the same cylinder reduce the engine efficiency because the timing of the combustion is rarely optimum. A method is needed which would ignite the mixture in a more repeatable manner and increase the effective flame speed (if possible) in the combustion chamber.